The present invention relates to trucks, and in particular relates to provision of mechanical support for portions of an engine exhaust outlet system for a heavy-duty truck.
It is common to place a muffler in an exhaust system for a heavy-duty semi-trailer truck in a vertical orientation, with an exhaust outlet pipe, or stack, extending further upward above the top of such a muffler to emit exhaust gases from the engine of such a large truck at some distance above the cab of the truck, so that exhaust gases will be dissipated quickly without being drawn into the cab. Locating such vertically-oriented mufflers behind the cab of such a large truck is desirable for various reasons which do not relate to the present invention. In the past, however, the mechanical supports for the exhaust system of such large trucks, and in particular for the mufflers and upwardly-extending exhaust stacks of such trucks have usually included support framework mounted on the frame of the truck. Such support framework has included diagonal cross bracing to hold a muffler and stack securely, with no interconnection between the muffler or stack and the cab of such a large truck, at least partly because the cab of a large truck is usually supported on the frame through resilient mounting devices, to isolate the cab and its occupants from at least a part of the vibration experienced by the chassis of the truck. Such exhaust system support arrangements in the past have been somewhat expensive and have added undesirable weight to the trucks on which they are used.
Keller U.S. Pat. No. 5,649,685 discloses an apparatus for attaching a muffler to the rear of a truck cab that does permit relative movement between the cab and the muffler. Unfortunately, the apparatus attaches to the front of the muffler, allowing the muffler to travel only along an arc of fairly small radius, which couples vertical movement with considerable unneeded and unwanted horizontal movement.
What is desired, then, is a support system, for a portion of an exhaust system including a vertically oriented muffler and stack, which is of simpler construction than has previously been known, yet which provides ample resilient support for such muffler and stack without interfering with the isolation of the cab from the frame of such a truck.